Lifting device



5 Sheets-Sh'get l.

IN VEN TOR. /0/7 K A. l/a rr ,la rnv ff. JPI

A TTORNEY l. K. HOTT ET AL LIFTING DEVICE Filed Feb. 2, 1925 Feb. I9,1929'.

Patented Feb. 19, 1929.

UNITED STATES ON V. K.'HOTT AND WALTER A. SPEAK, 0F DAYTON, OHTO,ASSGNORS TO THE JOYCE- PATENT s oFFlcE.

CRIDLAND COMPANY,`OF DAYTON, OHIO, A CORPORATION OF OHIO.

LIFTING DEVICE.

Application mea February 2, 1925. serial No@ 6,318.

This invention relates to lifting devices and more particularly to thetype of lifting device known as a double-acting pawl and ratchet jack.

One object of the invention is to provide improved means for controllingthe operation of the pawls of such a ack.

A further object of the invention is to provide controlling means forsaid pawls which will insure their accurate and positive operation andthus positively control the load on v the jack. n c

A further object of the invention is to -provide such a controllingmeans which will be simple in construction, inexpensive of manufactureand which will not be easily broken or disarranged in operation.

Other objects of the invention will appear as the mechanism is describedin detail.

ln the accompanying drawings Fig. 1 is a side elevation of a jackembodying our invention; TEig. 2 is a front elevation of the same,partly broken away; Fig. 3 is a sectiontalren on the line 3 3 of Fig. 2,showing the pawls in their lifting positions;-Fig. 4 is a similarsection showing the pawls in their initial low-` ering positions; andFig. 5 is a detail view showing the pawls in their elevated loweringpositions.

In these drawings we have illustrated one embodiment of our inventionand have shown the same as applied to a ack of the pawl and ratchet typeembodying a lifting element haviney teeth with which the pawls may beengaged, but it will be understood that the invention may take variousforms andinay be applied to pawl and ratchet jacks of various kin dsregardless of whether or notthe toothed element constitutes the liftingelement or-is separate therefrom. f

In that embodiment of the invention here shown the j ack comprises anupright hollow standard or supporting frame 1 having'its lower endenlarged, as shown at 2, to constitute a base. Slidably mounted inthisjack is a lifting element 3 having at its upper end a load engagingmember or cap 4. In the present jack, the lifting element is in the formof a bar and is provided in one edge with ratchet teeth, as shown at 5.Mounted on the standn ard or supporting frame 1 is a pawlsupporting'member which, as here shown, comprises a trunnion 6 journaledin the side members of the supporting frame and having an enlargedcentral portion 7 on which thelifting pawl is mounted. Connected withthe pawl supporting memberis an actuating member which is here shown inthe form of a lever socket 8 krigidly secured to the pawl supportingmember and adapted to receive the usual hand lever, by means of whichthe jack is opy ranged 'above the lifting pawl!) -is a detent pawl 11which. askhere shown, vis pivotally mounted on a shaftor trunnion 12mounted inthe sidewalls of the supporting frame and is movableabout-.the axis of said trunnion into and out of engagement withtheteeth of the lifting member. The pawl is, in the present instance,provided with a double nose, as shown at 13, so that it will engage twoteeth on the toothed member. Extending alongside of the lifting element3 is a bar 14 which is connected with, but is capable of movementrelatively to, both the lifting pawl 9 and the detent pawl 11, andassociated with this bar aresprings which act on the respective pawls tocontrol the positions thereof. The lifting pawl 9 has rigidly securedthereto, and'preferably formed integral therewith, an apertured lug 15and the detentpawl has rigidly secured thereto and preferably formedintegral therewith an apertured lug 16. The

rod 14 is mounted in these apertured lugs for both longitudinal bodilymovement with relation to the lugs and for tilting movement in the lugs.`As here shown, thelugs extend rearwardlyand laterally fromtherespective pawls so that the barc14 is supported alongside of thelifting element. The bar 14 has secured thereto, substantially midwaybetween its ends, a stop, which is preferably the form of a collar 17rigidly secured to the bar. At its lower and upper ends the bar hassecured thereto other stops which, in the present instance, are in theform of nuts 18and 19 screwthreaded onto the ends of the bar so as toprovide adjustable stops. The apertured lug 15 of the lifting pawlembraces the bar 14 above the lower stop 18 and a spring 20 is coiledabout the bar between the lug 15 *and the intermediate stop 17. Theapertured lug 16 of the detent pawl embraces the bar above theintermediate stop 17 and a spring 21 is coiled about the bar between thelug 16 and the upper stop 19. In the operation of the present jack thebar 111 is held against vertical movement during the lifting operationand to this end a suitable stop is provided which may be moved into andout of the path of the bar. As here shown, this stop is in the form ofan elongated plate 22 pivotally mounted at its rear end on thesupporting frame or standard 1 and having its forward portion 28inclined with relation to its rear portion to form a contact memberwhich is adapted to be engaged by a dog 24 pivotally mounted on theforward portion of the standard and provided in front of the standardwith an operating` handle 25. lf desired, the standard may be provided,adjacent to the handle 25, with a fixed hand grip 26 to facilitate thehandling of the jack and to guard the handle 25.

When the stop plate 22 is moved into locking position with relation tothe bar 14, as shown in Fig. 3, that bar will be forced downwardly, sothat the stops 18 and 17 will bc spaced from the apertured lugs 15 and16 and the springs 20 and 21 will be placed under compression so thatthey will act upon the lugs 1.5 and 16 to hold both pawls in operativeengagement with the toothed element. Consequently when oscillatorymovement is imparted to the lever the upward movement of the liftingpawl will elevate the lifting element, the detent pawl yielding topermit the passage of the teeth on the lifting element. Upon the reverseor downward movement of the lifting pawl the detent pawl will beretained in engagement with the teeth and will support the liftingelement against downward movement, while the lifting pawl will ride overthe teeth of the lifting el ement.

When the load is to be lowered the locking plate 22 is released so thatit offers no resistance to the movement of the bar 14. In Fig. 11 thepawls are shown in their initial lowering positions, that is, thelocking plate has been released and the pawls are ready for the loweringoperation. rll`he detent pawl 11 is in engagement with the teeth of thelifting element and these teeth overhang` the nose of the pawl in such amanner that it cannot be moved about its axis without imparting verticalmovement to the lifting element. The spring 21, which is confinedbetween the upper stop 19 on the bar 1% and the lug 16 of the detentpawl, serves to hold the bar in its upper position with the stop 17 inengagement with the lug 16 and the lower stop 18 in engagement with thelug 15 of the lifting pawl 9, which is in an inoperative position. Whenthe actuating lever is moved downwardly upward movement will be impartedto the lifting pawl and inasmuch as the bar 14; is held against upwardmovement by the stop 17 engaging the lug 16 the lower spring 2G will beplaced under compression and this compression increases the nose of thepawl will be moved into engagement with the teeth of the liftingelei'nent, the lower end of the bar swinging over or tilting to permitof this movement of the pawl. lhe parts are so shaped and arranged andtheir movements so timed that this lifting pawl will engage the toothedclement just before the lever completes its downward movement and,having engaged the toothed element, the further downward movement of thelever will cause the pawl to impart a slight elevation to the liftingelement. This upward movement of the lifting element is sufficient torelease the detent pawl 11 and the action of the lower spring 2() on thestop 17 will move the bar 1li upwardly and thus swing the detent pawlaway from the lifting element into an inoperative position. The vload isnow carried wholly on the lifting pawl and as the pressure on theoperating lever is relieved both the lifting element and the liftingpawl will move downward together. As the lifting pawl moves 'downwardlythe tension on the spring 2O is relieved and the lug` 15 on the liftingpawl engages the lower stop on the bar and moves that bar downwardly,fliers-bj,r exerting pressure on the upper spring 21 and causing thatspring to a'ct on the lug 16 of the detent pawl to move the detentpawlinto engagement with the toothed element. This movement is so timed thatthe det-ent pawl will not be moved into operative position until one ormore of the teeth of the lifting element have passed the same. Havingbeen brought into operative position the detent pawl will check thefurther downward movement of the toothed lifting element and the upperspring 21 will resist the further downward movement of the bar 141-. Thecontinued downward movement of thev lifting pawl, as the operating levercompletes its upward movement, will cause the lug 15 of the lifting pawlto engage the lower stop 18 on the bar and rock the pawl about its axisinto an inoperative position, thus restoring the parts to their initiallowering positions.

Cil

The repetition of this cycleV of voperations i causes the load to belowered step by step. v

While we have shown and described one embodiment of our invention wewish it to be understood that we do not desireto be limited to thedetails thereof as various modifications may occur to a person skilledin the art. f

Having now fully described our invention, what we claim as new anddesire to secure by LettersPatent, is: v

1. In a lifting device, a toothed element, a pawl supporting member, alifting pawl carried by said supporting member and movable into and outof lifting engagement with said toothed element, means for actuatingsaid supporting member to impart bodily movement t-o lsaid lifting.pawl, a detent pawl mounted independently of said lifting pawl 'and alsomovable into and out of engagement with said toot-lied element, a rigidbar slidably mounted on said paivls longitudinal moven'ient withrelation thereto, means for limiting the movement of said bar withrelation to said pawls, and springs carried by said bar and acting onthe respective pawls to control the positions thereof with relation tosaid toothed element.

` 2. In a lifting device, a toothed element, a pawl supporting member, alifting pawl carried by said supporting member and movable into and outof engagement with said toothed element, means for actuating saidsupporting member to impart b -dily movement to said lifting pawl, adetent pawl mounted independently of said lifting element and alsomovable into and out of engagement with said toothed element, a rigidbar supported by said pawls andcapable of longitudinal movement withrelation thereto, stops carried by said bar, lugs carried by therespective pa wls in fixed positions with relation thereto, and springsconfined between said stops and the respective lugs to control thepositions of said pawls with rela ion to sait toothed element. 3. In alifting device, a toothed element, a pawl supporting member, a. liftingpawl carried by said supporting member and movable into and out ofengage-ment with said toothed element, means for actuating saidsupporting member toimpart bodily movement to said lifting pawl, adetent pawl mounted independently of said lifting pawl and also movableinto and out of engagement with said toothed element, a rigid barconnected with and capable of longitudinal bodily movement with relationto both of said pawls, springs acting on said bar to impart longitudinalmovement thereto, and means to control the` longitudinal movement ofsaid bar with relay tion lto said pawls and thereby control the actionof said springs on said pawls.

4l. In va lifting device, a toot-lied element, a

pawl supporting member, a lifting pawl carried by said supportingmember' and movable into and out of engagement with said toothedelement, means for actuating said supporting member to impart bodilymovement to said lifting pawl, a detent pawl mounted in` dependently ofsaid lifting pawl, and also movable into and out of engagement with saidtoot-hed element, apertured lugs rigidly secured to the respectivepawls, a bar slidably mounted in said lugs, stops carried by said bar,and springs coiled about said bar and cooperating with said stops andsaid lugs to control the positions of said pawls with rclat-ion to saidtoothed element.

5.. lln a lifting device, a toothed element, a pawl supporting member, alifting pawl carried by said supporting member and movable into and outof engagen'ient with said toothed element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, adetent pawl mounted independently of said lifting pawl and also movableVinto andout of engagement with said toothed element, apertured lugsrigidly secured to the respective pawls, a bar slidably mounted in saidlugs, a stop carried by said bar between the ends thereof, other stopscarriedvby said bar near the respective ends thereof and spaced fromsaid intermediate stop, and; springs coiled-about said bar and confinedbetween said lugs and said stops to control the positions of said pawlswith relationto said toothed element.

6. In a lifting device, a toothed element, a pawl supporting member`,alifting pawl carried by said supporting member and movable into and outof engagement with said toothed element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, detcntpa'i'vl mountedindependently of saidlifting pawl and also mov-v ableinto and out of engagement with said toothed element, apertured lugscarried by the respective pawls, a bar slidably mounted in said lugs, astop carried by saidbar between the ends thereof, other stops carried bysaid bar near the respective ends thereof and spaced from saidintermediate stop, springs coiled about said bar and confined betweensaid lugs and said stops'to control thepositions of said pawls withrelation to said toothed element, andmeans for locking said bar againstupward movement.

7.111 a lifting device, a toothed element, a pawl supporting member,alifting pawl carried by said supporting member and movable into and outof engagement with said toothed element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, adetent pawl mounted indeoendentl* of said liftingn iawl and also movableinto and out of engagement with said toothed element,apertured lugscarried by the respective pawls, a slidably mounted in said lugs,intermediate` stop carried by said bar and lying beneath the lug of saiddetent pawl, a second stop carried by the lower.

portion of said bar and lying beneath the lug for said lifting pawl, athird stop carried by said bar and spaced some distance above the lugfor said detent pawl, a. spring confined between said intermediate stopand the lug for said lifting pawl, and a second spring confined betweensaid third stop and the lug for said detent pawl.v

8. In a lifting device, atoothed element, a pawl supporting member, alifting pawl carried by said supportinfr member and movable into and outof engagement with said toothed i element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, adetent p awl mounted independently of said lifting pawl and alsomovlable into and out of engagement with said toothed element, aperturedlugs carried by the respective pawls, a bar slidably mounted in saidlugs, an intermediate stop carried by said bar and lying beneath the lugof said detent pawl, a second stop carried by the lower portion of saidbar and lying beneath the lug for said lifting pawl, a third stopcarried by said bar and spaced some distance above the lug for said.detent pawl, a spring confined between said intermediate stop and thelug for said lifting pawl, a second spring confined between said thirdstop and the lug for said detent pawl, and means for moving said bardownwardly and retaining the same in its lower position, whereby saidsprings are compressed and caused to act upon the respective lugs tohold said pawls yieldably in engagement with said toothed element.

9. In a lifting device, a toothed element, a pawl supporting member, alifting pawl earried by said supporting member and movable into and outof engagement with said toothed element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, adetent pawl moimted independently of said lifting pawl and also movableinto and out of engagement with said toothed element, apertured lugscarried by the respective pawls, a bar slidably mounted in said lugs, anintermediate stop carried by said bar and lying beneath the lug of saiddetent pawl, a second stop carried by the lower portion of said bar andlying beneath the lug for said lifting pawl, a third stop 'carried bysaid bar and spaced some distance above the lug for said detent pawl, aspring confined between said intermediate stop and the lug for saidlifting pawl, a second spring confined between said third stop and thelug for said detent pawl, a locking plate movably mounted andoverlapping the upper end of said bar, and means for pressing saidlocking plate into engagement with the end of said -bar and retainingthe same in engagement therewith.

l0. in a lifting device, a toothed element, a pawl supporting member, alifting pawl carried by said supporting member and moyable into and outof engagement with said toothed element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, adetent pawl mounted independently of said lifting pawl and also movableinto and out of engagement with said toothed element, apertured lugscarried by the respective pawls, a bar slidably mounted in said lugs, anintermediate stop carried by said bar and lying beneath the lug of saiddetent pawl, a second stop carried by the lower portion of said bar andlying beneath the for said lifting pawl, a third stop carried by saidbar and spaced some distance above the lug for said detent pawl, aspring confined between said intermediate stop and the lug for saidlifting pawl,

a second spring confined between said third stop and the lug for saiddetent pawl, a locking plate pivot-ally mounted and overlapping theupper end of said bar, a pivoted dog arranged to engage said plate andto press the same, and a handle operatively connected with said dog. i

11. ln a lifting device, a toothed element, a pawl supporting member, alifting pawl carried by said supporting member and movable into and outof engagement with said toothed element, means for actuating saidsupporting member to impart bodily movement to said lifting pawl, adetent pawl mounted independently of said lifting pawl and also movableinto andout of engagement with said toothed element, a controllingmember supported by said pawls, and capable of longitudinalbodilymovement withv relation thereto, a stopV movable into a positionto limit the movement of. said member with relation to said pawls, andsprings confined between said member and the respective pawls.

ln testimony whereof, we afhx our signatures hereto.

ION V., K. HOTT. WALTER A. SPEAK.

